^th gen speedo fix

Discussion in 'General VFR Discussions' started by 300shooter, May 9, 2008.

  1. 300shooter

    300shooter New Member

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    I was wondering if anyone need how to adjust the speedo on an '03 or if it's even possible. I had a LEO radar me at 50km/hr and my speedo was reading 58 , pretty fair discrepancy and I'm not sure what it is at higher speeds, any thoughts?:confused:
     
  2. derstuka

    derstuka Lord of the Wankers Staff Member

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    Did you change your gearing? That could have done it. I do not believe you can adjust it, but if you could get a speedo healer if you did change your gearing.

    To be honest, bike speedos are not accurate really, just a round about number, and that doesn't really sound all that far off as far as bike speedos are concerned. My GPS had my FZR1000 8+MPH off at 85. At least it is reading fast....less likely to get a ticket then! haha!
     
  3. MrJoelieC

    MrJoelieC New Member

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    I have also found that the tire changes it as well... With my Old metzlers it was about as far off as your reading...I put on a set of Pilot Powers that have a little bit different ridge and are a bit taller and it does not seems as off.... Then again I was driving past one of those trailer things that says your speed...Those are notoriously off... meh I dunno....
     
  4. WhiteKnight

    WhiteKnight Well-Known Member

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    You could get a speedo healer. But if your speedo is reading fast, then that is a good thing to a point as it will most likely keep you out of tickets, but the drawback is that it adds a bit of mileage to your bike over all.
     
  5. grinder

    grinder New Member

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    Based on the comments of have heard and my own observations the speedo is about 10% high. Varies a bit with tires, tire wear etc. but overall about 10%.
     
  6. SCraig

    SCraig New Member

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    Motorcycle speedometers HAVE to read high. Certain jurisdictions (states, countries, towns, not sure what) have laws that speedometers can read xx% high but zero percent low.

    Keep in mind that when a motorcycle goes into a turn it leans. That lean causes it to run on the sides of the tires, which in turn effectively changes the radius of rotation. The radius, in turn, is what determines the length of one revolution of the tire (pi x diameter), which is then in turn what determines the speed. It doesn't matter whether the speedo drive is on the wheel or on the gearbox, the calculations are still made based on the length of a revolution of the tire.

    The only way the builders can insure that the speedometers don't read low in a curve is to cause them to read high on the straights.

    I've checked mine against my GPS, and it reads about 10% high in a straight line which is the accepted norm. The odometer reads correct, or within about 2% which is also the norm.
     
  7. keeena

    keeena New Member

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    I never thought about the turning scenario w/r/t a speedo healer...surprised I've never seen it come up in other SH discussions. I wouldn't have thought that the tire's diameter difference straight vs. leaned coupled w/ amount of time spent leaned over would've made much difference overall. So its interesting to hear that your ODO is that close to actual miles traveled.

    I adjusted mine to read close to exact while in a straight line, since thats the only time I care about knowing the speed. But if you're right, then my ODO will now be low. Maybe thats why my calculated MPG seems a bit low. :noidea:
     
  8. Tori

    Tori New Member

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    Go with a Speedo Healer. I love mine, and the install was easy peezy.
     
  9. 34468 Randy

    34468 Randy Secret Insider

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    There is also a cosign error in radar. The most accurate speed reading you will get from radar is if your bike is traveling directly towards the radar. Keep this up and someone gets hurt. So the radar is usually off to the side. If it is overhead, there is still the cosign error, just a different direction which makes no difference. Cosign error is the angle at which the radar beam is hitting it's target at. The cosign error without exception goes to the benefit of the vehicle. So the reading you get on radar is actually lower that the true speed of your vehicle.

    Sometimes this cosign error can be quite large. 10% is not beyond reason. When you couple this with the other issues raised here, it is easy to understand the big difference in the radar reading vs the speedometer reading you have.
    Clear as mud.

    I hear Styrofoam cups mounted on your front windscreen defeats radar. Any truth to this one?:rofl:
     
  10. 300shooter

    300shooter New Member

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    Gotcha, cosign error, that makes sense. As for the styrofoam cups, well I hear they only work if you line your brain bucket with tinfoil to keep out the alien radio frequencies and then adjust your flux capacitor for magnetic deviation........
     
  11. derstuka

    derstuka Lord of the Wankers Staff Member

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    use a GPS to calibrate your speed.....oh, and silly Randy, the styrofoam cups go on your helmet, silly wabbit...
     
  12. keeena

    keeena New Member

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    Or while you've got the bike on a dyno. I record speedometer values at Dyno speeds of 20, 40, 60, 80 and 100 mph.
     
  13. 34468 Randy

    34468 Randy Secret Insider

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    You must be my long lost twin.
     
  14. 34468 Randy

    34468 Randy Secret Insider

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    And you must be my long lost twin too. Hey. I must be a triplet !

    OOOPS. Just about forgot LG. Holey crap....Quads !:party2:
     
  15. eddievalleytrailer

    eddievalleytrailer Member

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    They all read fast. If you get a Speedo-Healer, It'll make the odometer run slow. The odometer is very accurate when stock. Only the speedo reads fast. My VFR is the worst of any of my bikes. My '03 ACE is pretty close (about 2% fast), but my '83 Ceptor is spot-on.
     
  16. Vlad Impaler

    Vlad Impaler New Member

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    Good speedo:
    [​IMG]
    Bad speedo:
    [​IMG]
    :unsure:
     
  17. 34468 Randy

    34468 Randy Secret Insider

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    MODS ! ! ! I didn't see anyone with a camera that day.
     
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